Violence against women is a significant social concern in the United States. Most women who are assaulted are attacked by someone they know. The consequences of these injuries to women are magnified by the costs of decreased occupational function by the victims, mental health services required by the victims, and services required by children of the victims who may also be abused by the male batterer. While primary and secondary prevention programs have great appeal, a more immediate method to reducing male violence against women is to identify arid treat the male batterer. Most male batterer treatment programs target the psychological or psychosocial origins of male violence against women. The results of these interventions have generally been promising though limited. One major limitation of psychological intervention is that it ignores recent research findings relevant to the biology of aggressive behavior and neglects to consider that for many male batterers, there may be "biological" factors which increase the risk and incidence of aggressive behavior against women. There is a substantial literature suggesting that biological factors, such as a reduction in central serotonergic (5-HT) system function, plays an important role in the expression of aggression. This neglect also closes off the possibility of any psychopharmacological intervention with which to enhance the efficacy of other more commonly used, psychosocial intervention strategies. Accordingly, the proposed project has two major specific aims. The first aim is a biological evaluation of the central serotonergic system of men who abuse their wives. The second aim is to test the efficacy of psycho pharmacologic (Fluoxetine) and psychologic (Cognitive-Behavioral Treatment: CBT) treatments in a 12-week "Acute Treatment Phase" and in a 24-26 week "Relapse/Prevention Phase". Biologic evaluation will include d- Fenfluramine Challenge (CSF 5-HIAA in a subgroup) and Platelet measures of 5-HT Uptake (3H-Paroxetine Binding) and 5-HT-2 receptors (125I-LSD Binding) to simultaneously assess multiple aspects of 3-HT system function. Treatment will be composed of four (4) arms: 1) CBT + Placebo (+ Ratings); 2) Fluoxetine + CBT (+ Ratings); 3) Fluoxetine + Ratings (No CBT); 4) Placebo + CBT (+ Ratings). The main hypotheses to be tested are: 1) male batterers have reduced central 5-HT system function in comparison with healthy controls and non-batterers; 2) Pretreatment 5-HT indices correlate with aggressive behavior in male batterers; and, 3) FLUOX (alone) and CBT (alone) are each more efficacious than Placebo in decreasing spousal abuse and that Fluoxetine and CBT are more efficacious than either treatment alone in the treatment of spousal abuse.